1. Field of the Invention
The present invention relates to a method for analyzing fundamental frequency information contained in voice samples, and a voice conversion method and system implementing said analysis method.
2. Description of Related Art
Depending on the nature of the sounds to be produced, production of speech, and in particular voiced sounds, may entail vibration of the vocal chords, which manifests itself through the presence in the speech signal of a periodic structure having a fundamental period, the inverse of which is referred to as the fundamental frequency or pitch.
In certain applications, such as voice conversion, aural rendering is of vital importance, and effective control of the parameters linked to prosody, including the fundamental frequency, is required in order to obtain acceptable quality.
Thus, numerous methods currently exist for analyzing the fundamental frequency information contained in voice samples.
These analyses enable the determination and modeling of fundamental frequency characteristics. For example, methods exist which enable determination of the slope or an amplitude scale of the fundamental frequency over an entire database of voice samples.
Knowledge of these parameters enables modifications of speech signals to be made, for example by fundamental frequency scaling between source and target speakers, in such a way as to globally respect the mean and the variation of the fundamental frequency of the target speaker.
However, these analyses enable only general representations to be obtained, and not fundamental frequency representations whose parameters can be defined, and are therefore not relevant, in particular to speakers whose speaking styles differ.
The object of the present invention is to overcome this problem by defining a method for analyzing fundamental frequency information of voice samples, making it possible to define a fundamental frequency representation whose parameters can be defined.